Devices utilizing ultrasonic waves at megahertz (MHz) frequencies are used in many applications such as ultrasonic non-destructive evaluation of sample materials, ultrasonic imaging, ultrasonic ink printing, ultrasonic mixing, droplet dispensing for pharmaceutical and biological applications, and selective coating or plating of materials on substrates.
In virtually all of the above-mentioned applications, the core of the system consists of an ultrasonic transducer that converts electrical signals into ultrasonic signals and vice versa. The ultrasonic transducer is typically a piezoelectric plate formed between two metal electrodes. Other forms of ultrasonic transducers are also known in the art and may be used in various applications of ultrasonic energy.